Process for preparing polymethyl siloxanes and product



Patented J une 1 6, 1 953 UNITED STATES PATENT OFFICE PROCESS FOR2,642,411 PREPARING POLYMETHYL SILOXANES AND PRODUCT Pierre JeanChevalier, Lyon, France, assignor to Societe Des Usines ChimiquesRhone-Poulenc,

Paris, France, a French body corporate No Drawing. Application November28, 1949, Se-

rial No. 129,883. In France December 7, 1948 methyl polysiloxanes can beobtained by distill;

ing under reduced pressure methyl polysiloxane.

resins having a CH32Si ratio lower than'or'at. the most equal to 1.4,such resins being prepared by hydrolysis at room temperature .of anethereal solution of. methyl chlorsilanes. These new fluid methylpolysiloxanes, as described in the said copending application, can beused to advantage as a substitute for methyl polysiloxane resin for manypurposes. I i The CI-IzzSi ratio referred to above is the ratio ofmethyl groups to silicon atoms in the mole-.; cule. In order to avoidany' ambiguity in the present description, it is to be understood thatthe term resin designates a product of the character which resultsdirectly. from the hydrolysis of methyl chlorsilanes without separa-.tion of any of the components of the product, The term fluid methylpolysiloxan'es designates the substances of a lower degree ofcondensation, having the physical properties defined above, which formthe subject of said co-pending patent application.

According to thepresent invention new and valuable organosilicic resincompositions comprise mixtures of methyl polysiloxane resins having aCHz':Siratioof at most 1.4 with at least of their weight of fluid methylpolysiloxanes'. The said compositionsfdifier from the usual methylpolysiloxane resins which have not been treated to separate constituentsof low degree of condensation in that, .the proportion of fluid; methylpolysiloxanes is substantially higher than is ever present in suchresins as they are normally prepared. The new compositions have theadvantageous properties of the fluid methyl polysiloxanes alone in thatthey are fluid, they may be gelled at room temperature by the action ofsmall quantities of lead naphthenate and they are stable on storage.

The new compositions may be prepared by adding fluid methylpolysiloxanes to methyl polysiloxane resins (the latter may or may notalready contain a certain proportion of unseparated fluid methylpolysiloxanes).' An alternative method of preparation consists inhydrolysing an ethereal solution of methyl chlorsilanes by means of amoderate 'quantity of water initially at 7 room temperature, for examplebetween 1 and -10 times ,the quantity theoretically necessary for thehydrolysis of the methylchlorsilanes since. in this way a fluid productis obtained which consists of a methyl 'polysiloxane resin alreadycontaining 30% or more of fluid methyl poly-f siloxanes. The quantity.of water. theoretically necessary for the hydrolysis of thechlorsilanes.

is 1 molecule of water for'each 2 atoms of -chlo-' rme- Theorganosilicic resin compositions of this invention can be used assubstitutes bothior the fluid methyl polysiloxanes of the co-pendingapplication, and also for the usual methyl polysiloxane resins, for agreat number of purposes, for example for the manufacture of mouldable'compositions.

*The following examples,in which the parts are by weight, will serve toillustrate the inven tion but are not to be regarded as limiting it inany way. I f

Example I "d'solution of 435 parts of a mixture of methyl chlorsilanes.having-a CHazSiratio equal to 1.25 V

in 1500 parts of ether is poured into 3'75 parts of water at roomtemperature and the ether vaporized by the reaction is condensedandreturned into the apparatus. The ethereal layer is separated and theether evaporated off, leaving a resin from which, by distillation underreduced pressure, of its weight of fluid methyl polysil'oxane distillingat .120, to 250 C; under pressure of 8mm. of mercury can be separated.The resin is fluid owing to itshigh content of fluid methyl polysiloxaneand remains fluid even on; prolonged storage in the. absenceof'solvent';

Ea:ample II A methyl polysiloxane resin is obtained by add 5 ing 2250parts of Water to a solution of 868 parts months in the absence of anysolvent without any appreciable increase in its viscosity. It can beused as a substitute for the usual methyl polysiloxane resins in themajority of their applications.

I claim:

1. A process for the production of fluid com positions of matter whichcomprises hydrolysing a solution in diethyl ether of methylhalogenosilanes having a CH3zSi ratio of at most 1.4 by pouring the saidsolution into a quantity of liquid water at room temperature equal to lto times the quantity theoretically necessary for the hydrolysis; thesaid methyl halogenosilanes being the sole halogenosilane employed, thesaid liquid water being the sole hydrolysing agent employed, and thediethyl ether being the sole organic solvent present; condensing andreturning the ether vaporized by the reaction to the hydrolysedsolution; separating the diethyl ether layer from the aqueous layer andrecovering by evaporation of said ether a liquid compositionof matterconsisting essentially of a mixture of methyl polysiloxanes having aCH3zSi ratio of at most 1.4, 30 to 45% of the weight of which consistsof methyl polysiloxanes which have a Cl-I31Si ratio of at most 1.4,which contain 8 to silicon atoms in the polysiloxane molecule, whichboil at 120'to 250 0., under a pressure of 8 mm. of mercury, and whichgel under the action of lead naphthenate at room temperature.

2. A liquid composition of matter produced by the process whichcomprises hydrolysing a solution in diethyl ether of methylhalogenosilanes having a CH3:Si ratio of at most 1.4 by pouring the saidsolution into a quantity of liquid water at room temperature equal to 1to 10 times the quantity theoretically necessary for the hydrolysis; thesaid methyl halogenosilanes being the sole halogenosilanes employed, thesaid liquid water being the sole hydrolysing agent employed, and thediethyl ether being the soleorganic solvent present; condensing andreturning the ether vaporized by the reactionto the hydrolysed solution;separating the'diethyl ether layer. from the aqueous layer andrecovering by evaporation of said ether liquid composition of matterconsisting essentially of a mixture of methyl polysiloxanes having aCH3ZSl ratio of at most 1.4, 30 to 45% of the weight of which consistsof methyl polysiloxanes which have a CH3:Si ratio of at most 1.4, whichcontain 8 to 20 silicon atoms in the polysiloxane' molecule, which boilat 120 to 250 0., under a pressure of 8 mm. of mercury, and which gelunder the action of lead naphthenate at room temperature.

3. A process for the production of fluid compositions of matter whichcomprises hydrolysing a solution in diethyl ether of methylhalogenosibanes having a CH3zSi ratio between 1.25 and 1.4 by pouring the saidsolutioninto a quantity of liquid water at room temperature equal to 1to 10 times the quantity theoretically necessary for the hydrolysis; thesaid methyl halogenosilanes being the sole halogenosilanes employed, thesaid liquid water being the sole hydrolysing agent employed, and thediethyl ether being the sole organic solvent present; condensing andreturning the ether vaporized by the reaction to the hydrolysedsolution; separating the diethyl ether layer from the aqueous layer andrecovering by evaporation of said ether a liquid composition of matterconsisting essentially of a mixture of methyl polysiloxanes having aCH31Si ratio between 1.25 and 1.4, 30 to 45% of the weight of whichconsists of methyl poly-. siloxanes which have a CI-I3zSi ratio between1.25 and 1.4, which contain 8 to 20 silicon atoms in the polysiloxanemolecule, which boil at to 250 C., under a pressure of 8mm. of mercury,and which gel under the action of lead naphthenate at room temperature.

4. A liquid composition of matter produced by the process whichcomprises hydrolysing a solution in diethyl ether of methylhalogenosilanes having a CH3zSi ratio between 1.25 and 1.4 by pouringthe said solution into a quantity of liquid water at room temperatureequal to l to 10 times the quantity theoretically necessary-for thehydrolysis; the said methyl halogenosilanes being the solehalogenosilanes employed, the said liquid water being the solehydrolysing agent employed, and the diethyl ether being the sole.organic solvent present; condensing and returning the ether vaporized bythe reaction to the hydrolysed solution; separating the diethyl etherlayer from the aqueous layer and recovering by evaporation of saidether'a liquid composition of matter consisting essentially of a mixtureof methyl polysiloxanes having a CH3:Si ratio be-.

tween 1.25 and 1.4, 30 .to 45% of the weight of, which consists ofmethyl polysiloxanes which have a Cl-l3zSi ratio between 1.25 and,1.4,which contain 8 to 20 silicon atoms in the polysiloxane molecule, whichboil at 120 to .250"v 0., under a pressure of 8 mm. of mercury, andwhich gel .under the action of lead naphthenate at room temperature.

PIERRE JEAN CHEVALIER.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,258,218 Rochow' Oct. '7, 1941' 2,389,477 Wright et a1. NOV."20, 1945' 2,398,672 Sauer Apr. 16, 1946 2,405,041 Mathes et a1. July 30,1946 2,449,572 Welsh Sept. 21, 1948 2,465,188 Barry et al. -Mar. 22,1949 2,477,330 Doyle July 26, 1949 2,499,865 Iler Mar. 7, 1950 2,501,525Krieble et a1; Mar. 21, 1950' 2,516,047 De Coste July 18, 1950'2,584,835 Biduad Feb. 2, 1952 OTHER REFERENCES Patnode et al., Journ.Amer. Chem..Soc., vol. 68, March 1946, pp. 358 to 363. l

1. A PROCES FOR THE PRODUCTION OF FLUID COMPOSITIONS OF MATTER WHICHCOMPRISES HYDROLYSING A SOLUTION OF DIETHYL ETHER OF METHYLHALOGENOSILANES HAVING A CH3:SI RATIO OF AT MOST 1.4 BY POURING THE SAIDSOLUTION INTO A QUANTITY OF LIQUID WATER AT ROOM TEMPERATURE EQUAL TO 1TO 10 TIMES THE QUANTITY THEORETICALLY NECESSARY FOR THE HYDROLYSIS; THESAID METHYL HALOGENOSILANES BEING THE SOLE HALOGENOSILANE EMPLOYED, THESAID LIQUID WATER BEING THE SOLE HYDOLYSING AGENT EMPLOYED, AND THEDIETHYL ETHER BEING THE SOLE ORGANIC SOLVENT PRESENT; CONDENSING ANDRETURNING THE ETHER VAPORIZED BY THE REACTION TO THE HYDROLYSEDSOLUTION; SEPARATING THE DIETHYL ETHER LAYER FROM THE AQUEOUS LAYER ANDRECOVERING BY EVAPORATING OF SAID ETHER A LIQUID COMPOSITION OF MATTERCONSISTING ESSENTIALLY OF A MIXTURE OF METHYL POLYSILOXANES HAVING ACH3:SI RATIO OF AT MOST 1.4, 30 TO 45% OF THE WEIGHT OF WHICH CONSISTSOF METHYL POLYSILOXANES WHICH HAVE A CH3:SI RATIO OF AT MOST 1.4, WHICHCONTAIN 8 TO 20 SILICON ATOMS IN THE POLYSILOXANE MOLECULE, WHICH BOILAT 120 TO 250* C., UNDER A PRESSURE OF 8 MM. OF MERCURY, AND WHICH GELUNDER THE ACTION OF LEAD NAPHTHAENATE AT ROOM TEMPERATURE.